U.S. patent application number 12/474431 was filed with the patent office on 2009-12-03 for method of producing sheet joined body.
This patent application is currently assigned to NITTO DENKO CORPORATION. Invention is credited to Naoyuki Matsuo.
Application Number | 20090294048 12/474431 |
Document ID | / |
Family ID | 41020742 |
Filed Date | 2009-12-03 |
United States Patent
Application |
20090294048 |
Kind Code |
A1 |
Matsuo; Naoyuki |
December 3, 2009 |
METHOD OF PRODUCING SHEET JOINED BODY
Abstract
The present invention relates to a method of producing a sheet
joined body, the method enabling an improvement in productivity of
the sheet joined body The method of producing a sheet joined body
according to the present invention includes blowing gas against
sheet members so as to bring the sheet members into tight contact
with each other to form tight contact parts and, at the same time,
irradiating the tight contact parts with laser light to join the
sheet members with each other, thereby producing a sheet joined
body
Inventors: |
Matsuo; Naoyuki;
(Ibaraki-shi, JP) |
Correspondence
Address: |
WESTERMAN, HATTORI, DANIELS & ADRIAN, LLP
1250 CONNECTICUT AVENUE, NW, SUITE 700
WASHINGTON
DC
20036
US
|
Assignee: |
NITTO DENKO CORPORATION
Osaka
JP
|
Family ID: |
41020742 |
Appl. No.: |
12/474431 |
Filed: |
May 29, 2009 |
Current U.S.
Class: |
156/272.8 |
Current CPC
Class: |
B29C 66/723 20130101;
B29C 66/9161 20130101; B29C 65/1635 20130101; B29K 2023/16
20130101; B29C 66/1142 20130101; B29C 66/73751 20130101; B29K
2023/06 20130101; B29K 2311/10 20130101; B29C 65/1629 20130101;
B29C 66/9221 20130101; B29C 66/71 20130101; B29C 66/7394 20130101;
B23K 26/0006 20130101; B23K 26/324 20130101; B29C 66/71 20130101;
B29C 66/919 20130101; B29C 66/71 20130101; B29C 66/8322 20130101;
B29K 2995/0027 20130101; B29C 65/1677 20130101; B29C 66/71
20130101; B29C 66/73161 20130101; B29C 66/73941 20130101; B29C
66/8266 20130101; B23K 2103/38 20180801; B29C 66/1162 20130101;
B23K 2101/18 20180801; B29C 66/71 20130101; B29K 2067/00 20130101;
B23K 2103/42 20180801; B23K 26/14 20130101; B29C 66/71 20130101;
B29C 65/168 20130101; B29C 66/729 20130101; B29K 2007/00 20130101;
B29C 65/1616 20130101; B29C 65/8215 20130101; B29C 66/81267
20130101; B29K 2007/00 20130101; B29K 2067/003 20130101; B29C
66/1122 20130101; B29C 66/71 20130101; B29C 66/71 20130101; B29C
66/71 20130101; B29C 65/8207 20130101; B29C 66/73921 20130101; B29C
65/7847 20130101; B29C 66/73752 20130101; B29K 2313/00 20130101;
B29K 2063/00 20130101; B29K 2023/12 20130101; B29K 2105/0854
20130101; B29K 2909/08 20130101; B29C 66/934 20130101; B29C 65/1654
20130101; B29C 66/836 20130101; B29C 66/939 20130101; B29C
2035/0822 20130101; B23K 26/244 20151001; B29C 66/71 20130101; B29C
66/8122 20130101; B29C 66/7392 20130101; B29C 66/43 20130101; B29K
2101/12 20130101; B29C 66/929 20130101; B29C 66/9241 20130101; B29C
66/8122 20130101; B29K 2023/06 20130101; B29K 2023/12 20130101;
B29K 2909/08 20130101; B29K 2023/16 20130101; B29C 66/116 20130101;
B29K 2023/10 20130101; B29K 2023/04 20130101; B29K 2059/00
20130101; B29K 2063/00 20130101 |
Class at
Publication: |
156/272.8 |
International
Class: |
B32B 37/00 20060101
B32B037/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 2, 2008 |
JP |
2008-144492 |
Claims
1. A method of producing a sheet joined body, which comprises
blowing gas against sheet members so as to bring the sheet members
into tight contact with each other to thereby form tight contact
parts, and, at the same time, irradiating the tight contact parts
with laser light to join the sheet members with each other, thereby
producing a sheet joined body
2. A method of producing a sheet joined body according to claim 1,
wherein the tight contact part of at least one of the sheet members
contains a thermoplastic resin
3. A method of producing a sheet joined body according to claim 1,
wherein air compressed by a compressor is used as the gas
4. A method of producing a sheet joined body according to claim 2,
wherein air compressed by a compressor is used as the gas
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority from Japanese Patent
Application No 2008 144492, which is incorporated herein by
reference
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a method of producing a
sheet joined body, and particularly, to a method of producing a
sheet joined body by abutting sheet members to each other,
irradiating the abutted part with laser light, thereby joining the
sheet members with each other to manufacture a sheet joined
body
[0004] 2. Description of the Related Art
[0005] Conventionally, a laser welding method has been used as a
method of producing a sheet joined body, the method involving
joining sheet members with each other to manufacture a sheet joined
body
[0006] The laser welding method is a method in which sheet members
are abutted to each other, the abutted part is then irradiated with
laser light to make the abutted part absorb and accumulate energy
of the laser light, and heating and melting the abutted part by
this energy to join the sheet members together by welding, to
thereby produce a sheet joined body
[0007] When an interface between the sheet members is irradiated
with laser light in such a condition that these sheets are
insufficiently brought into tight contact with each other, these
sheet members are insufficiently joined to each other by welding
and therefore there is a fear that a sheet joined body having
insufficient joint strength between the sheet members may be
formed
[0008] In view of the above, a method of producing a sheet joined
body is proposed in which the abutted sheet members to be brought
into tight contact with each other is irradiated with laser light
while these sheet members are pressed by a pressure fixing tool
such as a transparent glass plate (for example, Japanese Unexamined
Patent Publication No Sho 62 142092)
[0009] In such a conventional method of producing a sheet joined
body, a preparation step is carried out in which, for example,
firstly, a first sheet member 101 is laid on an upper surface of a
stage 103 and a second sheet member 102 is superposed on the first
sheet member 101 as shown in FIG. 5A
[0010] Next, as shown in FIG. 5B, a mounting step is carried out in
which a transparent glass plate 104 is mounted on an upper part of
the sheet member 102
[0011] Then, as shown in FIG. 5C, a joining step is carried out in
which the sheet members 101 and 102 are brought into tight contact
with each other and the second sheet member 102 is pressed downward
by using the transparent glass plate 104 so as to form tight
contact parts 105 and in this condition, the tight contact parts
are irradiated with laser light R to join these sheet members 101
and 102, thereby manufacturing a sheet joined body
[0012] Thereafter, the pressure applied to the second sheet member
102 by the transparent glass plate 104 is released to take out the
produced sheet joined body and further, as shown in FIG. 5D, a
detaching step is carried out in which the glass plate 104 is
detached from the sheet joined body 106
[0013] Then, as shown in FIG. 5E, a takeout step is carried out in
which the sheet joined body 106 is taken out
SUMMARY OF THE INVENTION
[0014] However, a conventional method of producing a sheet joined
body poses a problem that when sheet joined bodies are continuously
produced, a long period of time is required to carry out a mounting
step of mounting a pressure fixing tool such as a transparent glass
plate on an upper part of a sheet member and a detaching step of
detaching a pressure fixing tool from the sheet joined body,
resulting in low productivity Moreover, the pressure fixing tool is
deteriorated when it is used for a long term, giving rise to a
problem that the pressure fixing tool is an expendable supply
[0015] It is an object of the present invention to provide a method
of producing a sheet joined body, the method enabling an
improvement in productivity of a sheet joined body
[0016] According to the present invention, there is provided a
method of producing a sheet joined body that includes blowing gas
against sheet members so as to bring the sheet members into tight
contact with each other to thereby form tight contact parts and, at
the same time, irradiating the tight contact parts with laser light
to join these sheet members with each other, thereby producing a
sheet joined body
[0017] With the method of producing such a sheet joined body, the
method includes blowing gas to sheet members so as to bring the
sheet members into tight contact with each other to thereby form
the tight contact parts and, at the same time, irradiating the
tight contact parts with laser light to join these sheet members
with each other As a result, laser welding can be started more
quickly since the sheet members can be brought into tight contact
with each other without performing the mounting step carried out in
the conventional method of producing a sheet joined body Moreover,
after the laser welding is finished, a sheet joined body can be
taken out more promptly without the necessity to perform the
detaching step carried out in the conventional method of producing
a sheet joined body
[0018] Moreover, in the method of producing a sheet joined body
according to the present invention, the tight contact part of at
least one of the sheet members preferably contains a thermoplastic
resin
[0019] According to such a method of producing a sheet joined body,
the tight contact part of at least one of the sheet members
contains a thermoplastic resin and therefore, the tight contact
part containing a thermoplastic resin can be heated and melted by
laser light Therefore, this method has an advantage that the sheet
members can be directly joined with each other without the joining
member containing a thermoplastic resin Moreover, when the above
joining member is used, the tight contact part containing a
thermoplastic resin can also be heated and melted and therefore,
this method has an advantage that a sheet joined body with sheet
members having higher joint strength can be formed
[0020] Further, in the method of producing a sheet joined body
according to the present invention, air compressed by a compressor
is preferably used as the gas
[0021] According to such a method of producing a sheet joined body,
there is an advantage that the tight contact parts can be formed
using simple equipment such as a compressor and a pipe feeding the
air compressed by the compressor, without using complicated
equipment such as a pressure fixing tool and machines for operating
the pressure fixing tool which are used in the conventional method
for producing a sheet joined body
[0022] As mentioned above, the method of producing a sheet joined
body according to the present invention enables an improvement in
productivity of the sheet joined body
BRIEF DESCRIPTIONS OF THE DRAWINGS
[0023] FIGS. 1A to 1C are front views showing a method of producing
a sheet joined body according to an embodiment where FIG. 1A is a
preparation step, FIG. 1B is a joining step, and FIG. 1C is a
takeout step,
[0024] FIG. 2 is a side view showing a method of producing a sheet
joined body according to an embodiment,
[0025] FIG. 3 is a side view showing a method of producing a sheet
joined body according to an embodiment,
[0026] FIG. 4 is a front view showing a method of producing a sheet
joined body according to Example 1, and
[0027] FIGS. 5A to 5E are front views showing a method of producing
a sheet joined body according to related art
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0028] Hereinafter, an embodiment according to the present
invention will be described with reference to the attached
drawings
[0029] A method of producing a sheet joined body in the present
embodiment involves carrying out a preparation step of applying
sheet members to each other on a stage, a joining step of blowing
gas against the sheet members so as to bring the sheet members into
tight contact with each other to form tight contact parts and, at
the same time, irradiating the tight contact parts with laser light
to join these sheet members with each other, and a takeout step of
taking out the sheet joined body
[0030] In the preparation step, a first sheet member 10 is mounted
on a center of an upper surface of a stage 20 and a second sheet
member 11 is further mounted on the first sheet member 10 to
superpose the first and second sheet members 10 and 11 on each
other, as shown in FIG. 1A
[0031] In the joining step, as shown in FIG. 1B, gas G is blown
against the second sheet member 11 from above the second sheet
member 11 so as to bring the first sheet member 10 into tight
contact with the second sheet member 11 to form tight contact parts
40 and, at the same time, the tight contact parts 40 are irradiated
with laser light Then, applied laser light R is made to reach the
tight contact parts 40 to convert the light energy into heat energy
at these tight contact parts to join the first sheet member 10 to
the second sheet member 11 by welding
[0032] The second sheet member 11 has light transmittance for the
laser light R and the first sheet member 10 has a photo absorption
ability of absorbing the laser light R These characteristics bring
about such a situation that in the joining step, the laser light R
applied to the tight contact parts 40 is made to pass through the
second sheet member 11 and then to reach a surface of the first
sheet member 10 (surface on a side which is in contact with the
second sheet member 11), that is, the tight contact parts 40 to
convert the light energy into heat energy, thereby making it
possible to join the first sheet member 10 with the second sheet
member 11 by welding
[0033] It is to be noted that the first sheet member 10
unnecessarily has the photo absorption ability of absorbing the
laser light R When the first sheet member 10 does not absorb the
laser light R or insufficiently absorbs the laser light R, the
present invention may be embodied in a form in which a photo
absorbing agent is interposed between the first sheet member 10 and
the second sheet member 11, and the photo absorbing agent is
irradiated with the laser light R to heat the photo absorbing
agent, thereby joining the first sheet member 10 to the second
sheet member 11 by welding
[0034] A direction of the gas G to be blown is determined by a
guide section 30
[0035] Although there is no particular limitation to the guide
section 30 insofar as it determines the direction of the gas G to
be blown, a nozzle is given as an example of the guide section
30
[0036] Although no particular limitation is imposed on a shape of a
blow off opening of the nozzle, a circular shape and a square shape
are given as examples as the shape of the opening
[0037] No particular limitation is imposed on the direction of the
gas G to be blown against the surface of the second sheet member 11
insofar as the direction is within a range where the sheet members
10 and 11 can be brought into tight contact with each other to form
tight contact parts However, although there is no intention to
impose limitation, the gas G is preferably blown such that the
direction of the gas G to be blown is perpendicular to a surface of
the second sheet member 11 from a viewpoint of enabling the sheet
members 10 and 11 to be brought into tight contact with each other
while efficiently utilizing the gas G to be blown
[0038] An axis of the direction of the gas G to be blown and an
axis of the direction of the laser light R to be applied may be the
same or not insofar as the sheet members can be joined to each
other by welding to form a sheet joined body
[0039] However, the axis of the direction of the gas G to be blown
and the axis of the direction of the laser light R to be applied
are preferably the same from a viewpoint of easily applying the
laser light R to the tight contact parts formed by the gas G
[0040] A gauge pressure of the gas G is preferably not less than 0
01 MPa and less than 5 MPa and more preferably not less than 0 1
MPa and less than 2 MPa, although depending on the size of gas blow
off opening, the distance from a leading end of the gas blow off
opening to a part against which gas is blown, the direction of the
gas G to be blown against the surface of the second sheet member
11, materials of the first sheet member 10 and second sheet member
11 and the intensity of the laser light R to be applied
[0041] Since the pressure is not less than 0 01 MPa, the present
embodiment has an advantage that the first sheet member 10 and the
second sheet member 11 can be brought into tight contact with each
other more firmly, which can promote the welding Moreover, since
the pressure is less than 5 MPa, the sheet members can be prevented
from being fluttered by the pressure of the gas and therefore, the
present embodiment has an advantage that the sheet members are
easily secured at a set position
[0042] As a method of blowing gas, to the extent that the effect of
the present invention is not impaired, a method of blowing assist
gas which is used to scatter decomposed materials generated in a
laser cutting operation may be adopted
[0043] In the method of producing a sheet joined body according to
the present embodiment, the gas G is blown as mentioned above, so
that the sheet members 10 and 11 can be brought into tight contact
with each other to form the tight contact parts 40 without
performing the step of mounting a pressure fixing tool which step
is carried out in a conventional method of producing a joint sheet,
making it possible to start laser welding more promptly
[0044] The blowing of the gas G may be released just after the
irradiation with a laser is released or a short while after the
irradiation with the laser light R is stopped
[0045] The blowing of the gas G is preferably released a short
while after the irradiation with the laser light R is stopped and
more preferably released after the sheet members are joined from a
viewpoint of rapidly cooling the sheet members melted under heating
by irradiation with the laser light R to thereby be able to rapidly
join the sheet members with each other
[0046] Although the pressure of the gas after the laser irradiation
is released may be the same as the pressure of the gas when the
laser is applied, the pressure of the gas is preferably larger than
the pressure of the gas when the laser is applied as long as it is
within a range in which the formed sheet joined body is not blown
away, from a viewpoint of rapidly cooling the sheet members melted
under heating by irradiation with the laser light R to thereby be
able to rapidly join the sheet members with each other
[0047] No particular limitation is imposed on a method of applying
the laser light R in the joining step, and for example, a method in
which a spot beam is moved at a predetermined speed for scanning,
and a method in which a spot beam is fixed in position and the
stage 20 itself is moved at a predetermined speed for the relative
movement of the spot beam
[0048] In the joining step, the laser light R is applied such that
the laser light R transmits an upper portion of the second sheet
member 11 against which the gas G is blown
[0049] When scanning with the laser light R, it is preferred that
the scanning is performed together with the gas G
[0050] The leading end of the guide section 30 is positioned in any
direction with respect to the scanning direction of the laser light
R, and a case where the leading end of the guide section 30 is
positioned on a front side or a backside of the scanning direction
of the laser light R is given as examples
[0051] In the takeout step, a sheet joined body 12 is taken out
after the laser irradiation and the gas blowing are finished as
shown in FIG. 1C
[0052] In the takeout step, the sheet joined body can be taken out
promptly after the joining step without performing a step of
detaching a pressure fixing tool from the sheet members which step
is performed in the conventional method of producing a sheet joined
body
[0053] In the above embodiment, the first sheet member 10 and the
second sheet member 11 are overlapped on each other as shown in
FIGS. 1A to 1C However, the present invention is not limited
thereto and, for example, an end of the first sheet member 10 and
an end of the second sheet member 11 may be abutted against each
other as shown in FIG. 2
[0054] When the end of the first sheet member 10 and the end of the
second member are abutted against each other to produce a sheet
joined body in the above manner, no particular limitation is
imposed on the shape of the end of the sheet member 10 and on the
shape of the end of the second sheet member 11 insofar as these
shapes are those allowing the end of the first sheet member 10 and
the end of the second sheet member 11 to be abutted against each
other End surfaces of these sheet members may be, as shown in FIG.
2, a plane perpendicular to or, as shown in FIG. 3, a plane
inclined with the surface against which the gas is blown
[0055] In this case, at least one of the first sheet member 10 and
second sheet member 11 preferably has the photo absorbing ability
of absorbing the laser light When one of these sheet members has
the photo absorbing ability of absorbing the laser light, it is
preferable to apply the laser to the entire surface of the part
where the sheet member having photo absorbing ability is abutted
from a viewpoint that the entire surface of the abutted part is
easily joined by welding
[0056] When neither of these sheet members has the photo absorbing
ability of absorbing the laser light or sufficiently absorbs the
laser light, a photo absorbing agent may be interposed between the
first sheet member 10 and the second sheet member 11 and irradiated
with the laser light to heat the photo absorbing agent, thereby
joining these sheet members to each other by welding
[0057] In the above embodiment, the sheet members are secured to
each other by the gas blowing In the present invention, the sheet
members may be secured by sucking a sheet member from the stage
side in addition to the above gas blowing
[0058] Any method may be used as the method of sucking a sheet
member from the stage side without any particular limitation
insofar as it is a method of securing the sheet member to the
extent that the effect of the present invention is not impaired
Examples of these methods include a method in which a sheet member
is sucked from an opening formed on the stage part which is held in
contact with the sheet member
[0059] The number of the openings formed on the stage may be one or
two or more
[0060] Although there is no particular limitation to the shape of
the opening, a circular shape and a square shape are
exemplified
[0061] The sucking of the sheet member from the stage side has an
advantage that the fluttering of the sheet member caused by the
blowing of gas scarcely occurs
[0062] The first sheet member 10 and the second sheet member 11 to
be used in the method of producing a sheet joined body in the
present embodiment may have any of a monolayer structure or a
laminate structure without any particular limitation
[0063] Examples of these sheet members which may be adopted in the
present invention include polymer sheets using one or more of
thermoplastic resins such as a polyethylene resin (PE),
polypropylene resin (PP) and polyethylene terephthalate resin
(PET), heat curable resins such as an epoxy resin (EP) and phenol
formaldehyde resin (PF), natural rubber (NR) and rubber such as an
ethylenepropylenedien ternary copolymer (EPDM), woven fabrics or
nonwoven fabrics formed by synthetic fibers, natural fibers and
blended fibers constituted of these fibers, or composite sheets of
these materials
[0064] In the present invention, sheet members, at least one of
which is provided with the tight contact part containing a
thermoplastic resin, are used Alternatively, a joining member
containing a thermoplastic resin is interposed between the tight
contact parts Alternatively, when the sheet members are abutted
against each other, the tight contact parts are coated with a
joining member containing a thermoplastic resin In this manner, the
sheet members can be joined by welding at the tight contact parts
with laser light in the present invention
[0065] Even in a case of using this joining member, it is
preferable to use sheet members, at least one of which has the
tight contact part containing a thermoplastic resin If the tight
contact part of at least one of the sheet members contains a
thermoplastic resin, there is an advantage that a sheet joined body
having a higher joint strength between the sheet members can be
formed
[0066] When the surface of one of the sheet members is formed of a
material such as a metal material which is substantially scarcely
softened by heat, at least the surface to be joined by welding is
preferably roughened This produces such an effect that when another
sheet member is made of a thermoplastic resin or a joining member
containing a thermoplastic resin is used, and the thermoplastic
resin is softened by laser light, the softened thermoplastic resin
is flowed into the irregular surface of the metal material,
enabling a development of high joint strength by an anchoring
effect Further, the thermoplastic resin in the resin layer can be
softened owing to the high thermal conductivity of the metal
material, producing such an effect that the welding can be carried
out in a wide range by the thermoplastic resin of the softened
resin layer
[0067] A thickness of the sheet member to be used for the first and
second sheet members 10 and 11 is preferably not more than 200
.mu.m
[0068] The first sheet member 10 and the second sheet member 11 are
not necessarily the same but may be different in the material of
the sheet member, laminate structure, thickness and the like
[0069] The present embodiment shows an example using two sheet
members typified by the first sheet member 10 and the second sheet
member 11 However, three or more sheet members may be joined to
manufacture a sheet joined body in the present invention
[0070] Moreover, one end of the sheet member may be joined with the
other end of the same sheet member to produce an annular sheet
joined body in the present invention
[0071] Any laser light may be used as the above laser light without
any particular limitation insofar as the laser light can join the
sheet members to each other by welding As the laser light, those
obtained by various oscillation means such as semiconductor laser,
Nd YAG laser and fiber laser may be adopted In addition, as an
oscillation method, so called CW laser (Continuous Wave Laser) in
which laser light is continuously applied and pulse laser such as a
femto second laser may be adopted
[0072] Among these lasers, the semiconductor laser and the fiber
laser are preferable from a viewpoint of obtaining in plane uniform
beam intensity with ease
[0073] A wavelength of the laser light is preferably in a near
infrared region from a viewpoint that many resin materials have
high transmittance for the laser light having such a wavelength,
the laser light is easily made to reach an interface of the sheet
members, and the sheet members can be joined to each other by
welding at the interface without exerting an adverse influence on
the front side of the sheet member
[0074] Examples of the photo absorbing agent used to absorb the
laser light include pigments using porphyrin type compounds, dyes
and carbon black
[0075] Although no particular limitation is imposed on the type of
gas insofar as the gas enables the sheet members to be brought into
tight contact with each other at the interface between the sheet
members, examples of the type of gas may include gases such as air,
nitrogen, oxygen and inert gases
[0076] It is to be noted that the above gas is different from the
assist gas for which gases such as helium having a light weight are
preferably used from a viewpoint that decomposed products generated
in the cutting operation are easily scattered
[0077] As the above gas, air compressed by a compressor is
preferably used The use of the air compressed by a compressor as
the gas has an advantage that the above described tight contact
parts can be formed using simple equipment such as a compressor and
pipes for feeding the compressed air
[0078] Although not described in detail herein, technical
particulars relative to conventionally known methods of producing a
sheet joined body and sheet joined bodies may be adopted in the
method of producing a sheet joined body and sheet joined body
according to the present invention to such an extent that the
effect of the present invention is not impaired
EXAMPLES
[0079] The present invention will be described in more detail by
way of examples, however, the present invention is not limited
thereto
Example 1
[0080] As shown in FIG. 4, the following sheet member A was mounted
on the upper surface of a stage 20 and the end of the following
sheet member B was further mounted on the end of the sheet member A
to superpose the sheet member A on the sheet member B A photo
absorbing agent was applied to the interface between the sheet
members A and B to improve the ability of absorbing the laser
light
[0081] Gas G having a gauge pressure of 0 15 MPa was blown from the
following nozzle 30 against the upper part of the sheet member B
superposed on the sheet member A such that the both sheet members
were brought into tight contact with each other and at the same
time, the part against which the gas was blown was irradiated with
laser light R having a spot diameter of 2 mm.phi. by using a laser
light irradiation device so as to make the laser light R transmit
the part to manufacture a sheet joined body
[0082] In this case, the gas G was blown such that the distance
from a leading end of the nozzle 30 to the part against which gas
was blown was 30 mm Moreover, air compressed by a compressor was
used as the gas G Further, the gas G was blown such that the
pressure applied to the part of the sheet member B against which
the gas G was blown was 0 15 MPa in order to form tight contact
parts by bringing the sheet members A and B into tight contact with
each other Moreover, the laser light R was applied such that the
laser light R transmits the part of the sheet member B against
which the gas G was blown When the laser light R was applied, the
part against which the gas G was blown was scanned by moving the
emitting opening of the laser light R and the leading end of the
nozzle 30 at a scanning speed of 100 mm/s At this time, the
emitting opening of the laser light R and the leading end of the
nozzle 30 were moved by scanning while the leading end of the
nozzle 30 is positioned ahead of the emitting opening in a scanning
direction S
<Materials to be Used>
[0083] Sheet member A Polyethylene terephthalate resin (PET) sheet
material (50 mm (length).times.50 mm (width).times.50 .mu.m
(thickness)) [0084] Sheet member B Polyethylene terephthalate resin
(PET) sheet material (50 mm (length).times.50 mm (width).times.50
.mu.m (thickness))
<Laser Light Irradiation Device>
[0084] [0085] Laser light source Semiconductor laser [0086]
Wavelength of laser light 940 nm [0087] Power 20 W [0088] Spot
diameter of the laser light 2 mm.phi.
<Nozzle>
[0088] [0089] Blowing nozzle diameter 5 mm.phi.
[0090] A tensile test was made to examine the joint strength
between the sheet members A and B, to find that the joint strength
was 50 N/cm
[0091] In addition, since the abutted sheet members A and B on the
stage could be brought into tight contact with each other quickly,
the laser welding could be started promptly Further, after the
laser welding was finished, the produced sheet joined body could be
taken out promptly from the surface of the stage
Comparative Example 1
[0092] An attempt was made to manufacture a sheet joined body in
the same manner as in the case of the sheet joined body of Example
1 except that no gas was blown
[0093] The sheet member A was scarcely joined with the sheet member
B and therefore, no sheet joined body could be manufactured
Comparative Example 2
[0094] An attempt was made to manufacture a sheet joined body in
the same manner as in the case of the sheet joined body of Example
1 except that gas was blown under a pressure lower than the range
within which the sheet members could be brought into tight contact
with each other, specifically, under a gauge pressure of 0 005
MPa
[0095] The sheet member A was scarcely joined with the sheet member
B and therefore, no sheet joined body could be manufactured
Specifically, the method of Comparative Example 2 in which laser
light was applied with blowing gas under a pressure lower than the
range within which the sheet members could be brought into tight
contact with each other failed to produce a sheet joined body
Comparative Example 3
[0096] An attempt was made to manufacture a sheet joined body in
the same manner as in the case of the sheet joined body of Example
1 except that gas was blown under a pressure higher than the range
within which the sheet members could be brought into tight contact
with each other, specifically, under a gauge pressure of 5 MPa
[0097] The sheet member A was scarcely joined with the sheet member
B and therefore, no sheet joined body could be manufactured
[0098] Specifically, the method of Comparative Example 3 in which
laser light was applied with blowing gas under a pressure higher
than the range within which the sheet members could be brought into
tight contact with each other failed to produce a sheet joined body
because the pressure of gas causes the sheet members to flutter so
that the sheet members could not be secured at the set position
Comparative Example 4
[0099] A sheet joined body of Comparative Example 4 was
manufactured in the same manner as in the case of the sheet joined
body of Example 1 except that a transparent glass plate was used
instead of bringing the sheet members into tight contact with each
other by using gas
[0100] Specifically, firstly, the sheet member A was mounted on the
upper surface of the stage and the end of the following sheet
member B was mounted on the end of the sheet member A to superpose
the sheet members A and B on each other A transparent glass plate
was then mounted on the upper part of the sheet member B
Thereafter, laser light was applied to the superposed part with
pressing the transparent glass plate against the sheet member B
such that the pressure applied to the upper part of the sheet
member B was 0 15 MPa Subsequently, the pressure of the glass plate
against the sheet member B was released to detach the sheet member
from the glass plate, thereby manufacturing a sheet joined body
[0101] A tensile test was made to examine the joint strength
between the sheet members A and B, to find that the joint strength
was 50 N/cm
[0102] However, in the method of producing a sheet joined body in
Comparative Example 4, much time was taken to carry out the step of
mounting a transparent glass plate on the upper part of the sheet
member B and the step of detaching the glass plate from the sheet
member B
[0103] In other words, it was shown that time required for a
production process was longer in the method of producing a sheet
joined body in Comparative Example 4 in which the sheet members
were brought into tight contact with each other by using a
transparent glass plate compared to the method of producing a sheet
joined body in Example 1 in which the sheet members were brought
into tight contact with each other by using gas
[0104] This specification is by no means intended to restrict the
present invention to the preferred embodiments set forth therein
Various modifications to the method of producing the sheet joined
body, as described herein, may be made by those skilled in the art
without departing from the spirit and scope of the present
invention as defined in the appended claims
* * * * *